/Engine/Source/Runtime/Engine/Classes/Engine/Brush.h
An array to keep track of all the levels that need rebuilding. This is checked viaNeedsRebuild()in the editor tick and triggers a csg rebuild.
static [TArray](API\Runtime\Core\Containers\TArray)< [TWeakObjectPtr](API\Runtime\Core\UObject\TWeakObjectPtr)< [ULevel](API\Runtime\Engine\Engine\ULevel) > > LevelsToRebuild;